Most aneurysms -- abnormal bulges or ""ballooning"" in the wall of an artery -- occur in the aorta. The aorta is the main artery that carries blood from the heart to the rest of the body.

There are two types of aortic aneurysm:

• Thoracic aortic aneurysms occur in the part of the aorta running through the chest.
• Abdominal aortic aneurysms occur in the part of the aorta running through the abdomen.

Because aneurysms can develop and become large before causing any symptoms, it is important to look for them in people who are at high risk. Ultrasound screening for abdominal aortic aneurysms is recommended for men who have ever smoked and are between the ages of 65 and 75. Medicines and surgery are the two main treatments for aneurysms.

National Heart, Lung, and Blood Institute